It is conventionally proposed producing hexafluoroacetone hydrates with such various applications by the following methods:

(Non-Patent Document 1)

(Patent Document 1)

(Patent Document 2)

(Patent Document 3)

(Patent Document 4)
However, these methods each have defects, such as production of a large amount of industrial waste, low purity of the product, high toxicity of the reagent used, and corrosion of the reactor. None of these methods is thus economically or environmentally advantageous.
The present applicant has previously proposed a method for producing hexafluoroacetone or a hydrate thereof via an intermediate ozonide compound:
produced by subjecting heptafluoroisobutenyl alkyl, aryl, or benzyl ether (CF3)2C═CFOR to ozone oxidation (Patent Document 5).
Reaction examples of subjecting a carbon-carbon double bond chain to ozone oxidation to produce an ozonide intermediate, and subjecting the ozonide intermediate to a reduction reaction to convert it into a carbonyl group are known. Some of such examples are shown below:                Patent Document 6 describes the production of a prostaglandin synthetic intermediate, wherein the butenyl group of a synthetic starting material is subjected to ozone oxidation, followed by a reduction reaction in the presence of triphenylphosphine (Examples 30 and 32).        Patent Document 7 describes the production of a steroid derivative, wherein a carbon-carbon double bond is subjected to ozone oxidation, and the obtained ozonide is subjected to a reduction reaction in the presence of dimethyl sulfide (Reference Example 1).        Patent Document 8 describes subjecting a 4-alkyl-5-alkenylthiazole compound to ozone degradation, and subjecting the obtained ozonide compound to a reduction reaction in the presence of a reducing agent, such as lower alkyl disulfides, aryl phosphines, alkyl phosphines, alkyl phosphites, aryl phosphites, alkali metal bisulfites, alkali metal metabisulfites, alkali metal sulfites, alkali metal dithionites, thiodi-lower alkyl alcohols, thiodi-lower alkyl carboxylic acids, thiodialkylnitriles, thiodiphenols, or thiocarbamides.        
Here, dimethyl sulfide, diethyl sulfide, dipropyl sulfide, etc., are shown as examples of lower alkyl disulfides. Dimethyl sulfide is used in Example 14 of Patent Document 8. When this ozonide compound reducing agent is used (Example 14), the target 4-methyl-5-formylthiazole is obtained with the highest yield, as compared to when other ozonide compound reducing agents are used. Diethyl sulfide and dipropyl sulfide are considered to also have the same effect as that of dimethyl sulfide.